In making bags from thermoplastic film two basic bag configurations are often used. One bag configuration is the end-seal bag where a seamless tube of thermoplastic material is sealed and severed in the lay-flat condition at discrete intervals along its length to form bags. The other configuration is the side-seal bag where a sheet of film is folded so that the fold forms the bottom of the bag and then a series of seals are made transversely to form the sides of the bag. Examples of both of these types of bags are shown in U.S. Pat. No. 3,979,058 which issued on Sept. 7, 1972 to Philip F. Cilia. Another example of a side-seal bag is shown in U.S. Pat. No. 3,647,060 which issued on Mar. 7, 1972 to Robert R. Kiely.
A bag which is a combination in some respects of both the side-seal and end seal bag is one which is formed by collapsing a seamless tube to a lay-flat condition, removing a narrow longitudinal strip from one side of the lay-flat tube, the strip being transversely spaced from one side of the lay-flat tube at a distance equal to the desired lip extension and then transversely sealing the tube at regular longitudinal intervals to create a series of bags. One of the advantages of the side-seal bags is that they can be made in a detachable or dispensable form by providing perforations or serrations between the two adjacent side seals of side-by-side bags in a chain of bags. Such arrangements are shown in U.S. Pat. No. 3,033,257 which issued on May 8, 1962 to H. H. Webber and in U.S. Pat. No. 3,160,273 which issued on Dec. 8, 1964 to R. H. Reuther et al. Still other appropriate examples of this type of bag are found in U.S. Pat. No. 4,493,684 which issued on Jan. 15, 1985 to Roderick A. Bolton and in Spanish Utility Model No. 259,143 which issued on Apr. 23, 1982 in the name of W. R. Grace and Co.
Because side-seal bags are readily detachable, can be made in a variety of widths and lengths, and can be supplied in a roll without the necessity of tapes, clips, or wickets they have received a great deal of attention for automatic loading processes. One example of an apparatus for separating and loading bags of a chain of side-seal bags is U.K. Pat. No. 2,080,179. A method for loading such bags is disclosed in U.K. Pat. No. 2,087,654.
It is a general object of the present invention to utilize a chain of side-seal bags, particularly side-seal bags that have a lip which can be gripped, in a relatively high-speed process.
It is another object of the present invention to load a plurality of side-seal bags simultaneously.
It is still another object of the present invention to provide a method and apparatus in which one plurality of bags is being brought to a loading station while a preceding plurality of bags is being loaded in the station.
These and other objects and advantages of the present invention will be more readily understood from the following Summary of the Invention, Description of the Drawings, and Description of the Preferred Embodiment.